SU834739A1 - Device for displaying graphic information on crt screen - Google Patents

Description

The invention relates to computing technology and can be used in designing graphic information display devices. A device for reproducing graphical information containing multipliers, counters, digital-to-analog converters, etc. is known. . The closest in technical essence to the present invention is a device for displaying graphical information on the screen of a cathode ray tube, but each of the coordinates contains a series-connected reversible counter, a first digital-to-analog converter and a DC amplifier connected to a deflection system of the cathode ray tube, the control unit connected with one of the inputs of the reverse counters and a code bus connected to one of the inputs of the synchronizer, the address bus Hz tkom known devices is the low precision devices | 3a of the small discreteness when forming IMAGE voltage. The purpose of the invention is to improve the accuracy of the device. The goal is achieved in that the device contains a digital differential analyzer, two OR elements, two binary switches and a frequency division unit connected to another synchronizer input connected to one of the digital differential analyzer's iodines, the other input of which is connected to the code bus, the outputs digital differential analyzer is connected to one of the inputs of the OR elements, the other inputs of which are connected to another output of the synchronizer, the outputs of the elements OR are connected to one of the inputs in binary multipliers, the other inputs of which are connected to the bus of the code, the binary outputs of the multipliers are connected to the other vhoDs1M reversible counters. The drawing shows a block diagram of a device that contains a control block 1, a frequency division block 2, a synchronizer 3, a digital differential analyzer DACS) 4, elements 5 and 6 OR, binary multipliers 7 and 8, reversible counters 9 and 10, the first and second D / A converters 11 and 12, DC amplifiers 13 and 14,. connected to the deflection system 15 of the CRT 16, the address 17 and the code 18 bus. Bus 17 is designed to provide address codes defining a specific receiver of code information. Bus 18 is used to supply data codes necessary for displaying graphic information. (Command words, slnp codes, vector slope, vector length code & L, scale factor code K for dividing the frequency in accordance with the selected display speed of the primary scan , the position codes Hit, the code points of the initial phases of the displayed circle or arc, the code R of the displayed circle, the code g of the angular size of the displayed arc). The input of block 2 is supplied with a sync series with frequency f. When displaying vectors and scanning lines at each moment of time, the correlation between the deviation signals along the orthogonal axes and the corresponding digital codes Y - YO X - X „bbsp initial coordinates should be performed where XC ,, Y, points of the vector (scan line) ; coordinates of the current point of the vector (scanning line); the angle of inclination of the vector relative to the Y axis. Considering that Y L cos f5; where L is the current length of the p1 line of the pt screw), after differentiation, we obtain dx. ., dL -ar (2) Integrating in time and transition to the discrete recording form as a sum, we get X sInpJ3 ft K.At А AL elementary increments for the vector (scan line)) n is the number of elementary directions required for writing a vector (sweep line) of a given length Similar to k-At (4) Yfl + cosfb Y When displaying arcs and circles between a deviation signals along orthogonal axes and the corresponding center codes, the relationship X Y where X and Y are the coordinates of the current points of the arc (circle) IR - its radius. Taking into account that Y Rcos / ь, gder is the angle between the direction to the current point and the Y axis, and the transition to the differential trill, we get ai-SWsinf i (6; XR sinf}, we have r ,, V into the integral and writing the result of discrete form, we get I K4t (8) xn + R: taxically Y YO - RD sinfb the representation of vectors and lines of development in the device by forming the input signals C3) and C4) is performed by the method similar to that described in (1). The display of arcs and circles in the device is carried out by forming with dcd 4 two-synchronous time-pulse signals sfn and cos with ate food, we throw them intelligently by a code of radius. Correspondingly, the magnitude of the change in the signal at the input of the deflecting system of a CRT can be achieved by an elementary change in the digital grid function (8) and (e) causing the beam to move across the screen of a CRT that does not exceed its resolution element. In this case, the screen will display a continuous, smooth circle or arc with high quality playback. The operation of the entire device is controlled by a single control unit 1 using address codes received on bus 18 and command words supplied via bus 17. Command words contain information about the type of information displayed (sweep line, vector, arc, circle), the necessary operating information. the size of the device, the direction of the arc display (clockwise or counterclockwise). The control unit 1 provides all the units and elements of the device with the necessary recording pulses and signal control of the bits and counting modes and commutation signals. The control unit 1 may include an address code decoder, a co-writing write pulse to the corresponding information receiver at the appropriate time, a command word register with the information type code decryption schemes, trigger and logic circuits for storing the sign codes of the sin and cos function and the arc and direction display code the formation of the corresponding control signals of the counting modes of the counters 9 and 10 and the internal counters of the digital display unit 4, on which the functions sin and cos are formed. ION may include a memory register R (radius of the arc of the circle) with the elements forming a width of the control signals of the device. The frequency division unit 2 produces the necessary division of the input frequency fo. When displaying vectors, the division factor is equal to one. When displaying scanning lines, the frequency at the output of block 2 is determined according to the scale factor K written to the internal memory register of block 2 via bus 17. When the arcs and circles of issue two series of f-, and f related by the dependence f-, Ж / 2- f to fulfill the ratio

e T / 2 R,

where R is the radius of the circle j P is the length of the arc 90, corresponding to one cycle of operation of block 4. Multiplication by 7/2 is difficult. Therefore, the initial frequency f is divided into two blocks in a block and is treated as f-i f / 2. The same frequency f is multiplied by 7Г / 4 (since 7Г / 4 is a number less than one, this operation can be carried out in a special binary multiplier, which is part of frequency divider 2). In this case, the above relationship between and ff Synchronizer 3 in the mode of displaying arcs and circles forms a burst, the frequency of the pulses in which is equal to f. and the duration of a pack is determined by the write-off time of the arc length code р using the pulses at the frequency f.B in the mode of displaying vectors and scanning lines, the duration of the pack is determined by the time it takes to write off the code for the length of the line ui. pulses from the output of block 2 frequency division. The synchronizer 3 can be built on the basis of the structure, consisting of a register of the length of the subtractive code element with rewriting schemes and the gate trigger, and (and this is preferable in our case for achieving greater speed) based on a parallel reversible counter into which the second the input of the device - the code of the size of the wind or arc (d. or others), the decoder of the zero code of the counter and the trigger of the gate, prohibiting the passage of the pack when issuing the corresponding signal from the decoder, is entered. ZDL 4 is used only to display circles and arcs. It forms two sequences, the temporal arrangement of which

corresponds to the nature of the change in functions I p P and

The two elements 5 and 6 OR are used to select the desired time sequence. Depending on the control signals from control unit 1, pulse bursts pass through elements 5 and b, either from the outputs of the digital signs or from the second output of synchronizer 3. Binary multipliers 7 and 8 temporarily multiply the pulses of impulses fed to the BTOjaie inputs of these elements , on binary codes corresponding to cos (i in the mode of displaying vectors and scanning lines and R in the mode of displaying arcs and circles. In the reversible counters 9 and 10, binary codes of functions defined by the expressions (h) (4) or (3) are formed, C9). The codes of the initial positions X Q and YO are set in the counters through their first inputs; connected to a common code bus. The counting mode is controlled by control unit 1. Converters 11 and 12 convert digital codes X and Y into corresponding analog signals. DC amplifiers 13 and 14 amplify the signals from the output of converters 11 and 12 to values sufficient to control the deflection system 15 of the CRT 16.

Claims (1)

The CRT deflection system deflects the beam to a given point on the screen floor. Before starting the display of the vector, the following codes arrive in the display device of graphic information via bus 17, which, in accordance with the addresses synchronously arriving on bus 18, are recorded in the following blocks and elements: command word — in control unit 1, the initial position code Xd — into reversible counter 9; the initial position code YQ is in the reversible counter 10. Initial position codes come at the beginning of the initial information array so that the device is filled with all other information parallel to time with the transients in amplifiers 13 and 141 of the vector slope S i p fi - to binary multiplier 7, cos tilt code of the vector - to binary multiplier 8; vector length code AjL - to synchronizer 3 1 when displaying the scanning line in. The frequency division unit 2 records the scale factor code K. Simultaneously, the control unit 1, according to the information in the command words, connects the second inputs of elements 5 and b OR to the second output of the synchronizer 3 and outputs signals (controlling the counting modes to the corresponding reversible counter 9 and 10. An impulse to start displaying a series of pulses after block 2 of dividing the frequency falls into synchronizer 3, where a packet is formed on the recorded code fli, the number of pulses in which is equal to the AJJ code. Passage through binary multipliers 7 and 8 it is multiplied by the sin codes present (J isoses {The time-pulse sequences removed from the outputs of the multipliers form into reversible counters, x 9 and 10 codes, changing according to the law (3) and (4), which, being converted into analogue The signals in converters 11 and 12 are amplified in amplifiers 13 and 14 using the deflection system 15, controlling the beam path on the screen reproducing the straight line. Similarly to the case of reproducing vectors, before starting the display of arcs and circles, the following information is output : to andnoe word - in the control unit 1; the initial position code Xp is in the reversible counter 9; the initial position code YO is in the reversible counter 10; code s i p P-Q and the initial phase of the displayed arc (circle) - in CDA 4; the cosfio code of the initial phase of the displayed arc (circle-) is in CDA 4; code R - in binary multipliers 7 and 8; the code E | b of the angular size of the circle is sent to the synchronizer 3. In accordance with the information about the direction of the arc (circle) and its initial phase, com 1 control on the reversible counters 9 and 10, as well as on the DPA 4, counting signals are issued corresponding counters. After the arrival of the impulse of the start of the display according to the series given by the frequency dividing unit 2, the synchronizer 3 forms a burst of pulses with a duration equal to /) and with the filling. This bundle enters converter 4 as an increment of an independent variable. Two time-pulse functions f (t) slnfb f (t) are removed from the output of the transducer 4. D-fc The control unit 1 permits the passage of these signals to binary multipliers 7 and 8, where they are multiplied by the radius of the circle R. Integrating the resulting time-pulse sequence forms, at the outputs of the reversible counters 9 and 10, functions in accordance with expressions (8) and (9). These digital functions are converted into analog signals, which are then amplified and, when applied to the deflection system 15 of the CRT 16, control the deflection of the CRT beam by wave (circle). In the process of displaying the dut (of circles), the control unit 1 performs an operative estimation of the values of the functions generated. ZDL 4, and the corresponding change in the counting modes of the internal counters CDA 4 and reversible counters 9 and 10 when the sin and cos functions pass through a maximum and zero. In addition, to equalize the angle of all beam speeds when displaying arcs (circles) of different radii, the display of graphical information on the CRT screen provides for changing the size of digital blocks and elements, which is performed by control unit 1 after estimating the radius of the arc (circle). Due to this, the alignments of the velocities of the displayed arcs (circles) of different radius are made. Thus, the use of the proposed invention allows to increase the accuracy of arcs and circles displayed on a CRT screen, which, in combination with the ability to display vectors and scan lines in the same structure, meets the requirements for information display systems of radio engineering information systems. Modern CRTs provide 2 ° resolution elements per tube diameter (2 per radius). Based on this, the number of bits per circumference of the maximum radius is 2 / R 2T-2 2. When selected, the input to the third input of the device is 6l2 MHz. The total display time of the maximum radius circle is T 2 / f 2 1340 - 760 μs In formula (10), the value 2 / f is indicated, since the frequency fed to synchronizer 3,. Decreasing the radius proportionally decreases the display time. Apparatus of the Invention A device for displaying graphical information on a screen of a cathode ray tube containing, in each of the coordinates, a series-connected reversible counter, a first digital-to-analog converter, and a DC amplifier connected to the bending system of the cathode ray tube, a control unit connected to one of the reversible counter inputs and code bus connected to one of the inputs of the synchronizer and the address bus, it’s about the fact that, in order to improve the accuracy of the device Islands, it comprises a digital differential analyzer, two OR gates, two binary